When I move my vehicle, odomety does not move in rviz, I would appreciate your help. My arduino code is here;
#include "Motor.h"
#include <ros.h>
#include <ros/time.h>
#include <geometry_msgs/Twist.h>
#include <std_msgs/Int16.h>
#include<PID_v1.h>
ros::NodeHandle nh;
#define LOOPTIME 10
int updatenh;
Motor right(11,10,20,21);
Motor left(9,8,18,19);
volatile long encoder0Pos = 0; // encoder 1
volatile long encoder1Pos = 0; // encoder 2
double left_kp = 17 , left_ki = 0 , left_kd = 0.0; // modify for optimal performance
double right_kp = 20 , right_ki = 0 , right_kd = 0.0;
float demandx=0;
float demandz=0;
double demand_speed_left;
double demand_speed_right;
double right_input = 0, right_output = 0, right_setpoint = 0;
PID rightPID(&right_input, &right_output, &right_setpoint, right_kp, right_ki, right_kd, DIRECT);
double left_input = 0, left_output = 0, left_setpoint = 0;
PID leftPID(&left_input, &left_output, &left_setpoint, left_kp, left_ki, left_kd, DIRECT);
unsigned long currentMillis;
unsigned long prevMillis;
float encoder0Diff;
float encoder1Diff;
float encoder0Error;
float encoder1Error;
float encoder0Prev;
float encoder1Prev;
void cmd_vel_cb( const geometry_msgs::Twist& twist){
demandx = twist.linear.x;
demandz = twist.angular.z;
}
ros::Subscriber<geometry_msgs::Twist> sub("cmd_vel", cmd_vel_cb );
std_msgs::Int16 left_wheel_msg;
ros::Publisher left_wheel_pub("lwheel" , &left_wheel_msg);
std_msgs::Int16 right_wheel_msg;
ros::Publisher right_wheel_pub("rwheel" , &right_wheel_msg);
double pos_act_left = 0; //Actual speed for left wheel in m/s
double pos_act_right = 0; //Command speed for left wheel in m/s
void setup() {
nh.initNode();
nh.subscribe(sub);
nh.advertise(left_wheel_pub);
nh.advertise(right_wheel_pub); //prepare to publish speed in ROS topic
// Serial.begin(115200);
rightPID.SetMode(AUTOMATIC);
rightPID.SetSampleTime(1);
rightPID.SetOutputLimits(-100, 100);
leftPID.SetMode(AUTOMATIC);
leftPID.SetSampleTime(1);
leftPID.SetOutputLimits(-100, 100);
// Serial.println("Basic Encoder Test:");
attachInterrupt(digitalPinToInterrupt(left.en_a), change_left_a, CHANGE);
attachInterrupt(digitalPinToInterrupt(left.en_b), change_left_b, CHANGE);
attachInterrupt(digitalPinToInterrupt(right.en_a), change_right_a, CHANGE);
attachInterrupt(digitalPinToInterrupt(right.en_b), change_right_b, CHANGE);
}
void loop() {
currentMillis = millis();
if (currentMillis - prevMillis >= LOOPTIME){
prevMillis = currentMillis;
demand_speed_left = demandx - (demandz*0.1075);
demand_speed_right = demandx + (demandz*0.1075);
/*PID controller for speed control
Base speed being 1 ms and the demand_speed variables controlling it at fractions of the base.
The PID controller keeps trying to match the difference
in encoder counts to match with the required amount, hence controlling the speed. */
encoder0Diff = encoder0Pos - encoder0Prev; // Get difference between ticks to compute speed
encoder1Diff = encoder1Pos - encoder1Prev;
pos_act_left = encoder0Pos;
pos_act_right = encoder1Pos;
encoder0Error = (demand_speed_left*39.65)-encoder0Diff; // 3965 ticks in 1m = 39.65 ticks in 10ms, due to the 10 millis loop
encoder1Error = (demand_speed_right*39.65)-encoder1Diff;
encoder0Prev = encoder0Pos; // Saving values
encoder1Prev = encoder1Pos;
left_setpoint = demand_speed_left*39.65; //Setting required speed as a mul/frac of 1 m/s
right_setpoint = demand_speed_right*39.65;
left_input = encoder0Diff; //Input to PID controller is the current difference
right_input = encoder1Diff;
leftPID.Compute();
left.rotate(left_output);
rightPID.Compute();
right.rotate(right_output);
// Serial.print(encoder0Pos);
// Serial.print(",");
// Serial.println(encoder1Pos);
publishPos(LOOPTIME);
if(updatenh>10){
nh.spinOnce();
updatenh=0;
}else{
updatenh++;
}
}
}
//Publish function for odometry, uses a vector type message to send the data (message type is not meant for that but that's easier than creating a specific message type)
void publishPos(double time) {
int pos_act_left;
int pos_act_right;
left_wheel_msg.data = pos_act_left; //timestamp for odometry data
right_wheel_msg.data = pos_act_right; //left wheel speed (in m/s)
left_wheel_pub.publish(&left_wheel_msg); //right wheel speed (in m/s)
right_wheel_pub.publish(&right_wheel_msg); //looptime, should be the same as specified in LOOPTIME (in s)
nh.loginfo("Publishing odometry");
}
// ************** encoders interrupts **************
// ************** encoder 1 *********************
void change_left_a(){
// look for a low-to-high on channel A
if (digitalRead(left.en_a) == HIGH) {
// check channel B to see which way encoder is turning
if (digitalRead(left.en_b) == LOW) {
encoder0Pos = encoder0Pos + 1; // CW
}
else {
encoder0Pos = encoder0Pos - 1; // CCW
}
}
else // must be a high-to-low edge on channel A
{
// check channel B to see which way encoder is turning
if (digitalRead(left.en_b) == HIGH) {
encoder0Pos = encoder0Pos + 1; // CW
}
else {
encoder0Pos = encoder0Pos - 1; // CCW
}
}
}
void change_left_b(){
// look for a low-to-high on channel B
if (digitalRead(left.en_b) == HIGH) {
// check channel A to see which way encoder is turning
if (digitalRead(left.en_a) == HIGH) {
encoder0Pos = encoder0Pos + 1; // CW
}
else {
encoder0Pos = encoder0Pos - 1; // CCW
}
}
// Look for a high-to-low on channel B
else {
// check channel B to see which way encoder is turning
if (digitalRead(left.en_a) == LOW) {
encoder0Pos = encoder0Pos + 1; // CW
}
else {
encoder0Pos = encoder0Pos - 1; // CCW
}
}
}
// ************** encoder 2 *********************
void change_right_a(){
// look for a low-to-high on channel A
if (digitalRead(right.en_a) == HIGH) {
// check channel B to see which way encoder is turning
if (digitalRead(right.en_b) == LOW) {
encoder1Pos = encoder1Pos - 1; // CW
}
else {
encoder1Pos = encoder1Pos + 1; // CCW
}
}
else // must be a high-to-low edge on channel A
{
// check channel B to see which way encoder is turning
if (digitalRead(right.en_b) == HIGH) {
encoder1Pos = encoder1Pos - 1; // CW
}
else {
encoder1Pos = encoder1Pos + 1; // CCW
}
}
}
void change_right_b(){
// look for a low-to-high on channel B
if (digitalRead(right.en_b) == HIGH) {
// check channel A to see which way encoder is turning
if (digitalRead(right.en_a) == HIGH) {
encoder1Pos = encoder1Pos - 1; // CW
}
else {
encoder1Pos = encoder1Pos + 1; // CCW
}
}
// Look for a high-to-low on channel B
else {
// check channel B to see which way encoder is turning
if (digitalRead(right.en_a) == LOW) {
encoder1Pos = encoder1Pos - 1; // CW
}
else {
encoder1Pos = encoder1Pos + 1; // CCW
}
}
}